#ifndef _LINUX_MSG_H
#define _LINUX_MSG_H

#include <linux/ipc.h>

/* ipcs ctl commands */
#define MSG_STAT 11
#define MSG_INFO 12

/* msgrcv options */
#define MSG_NOERROR     010000	/* no error if message is too big */
#define MSG_EXCEPT      020000	/* recv any msg except of specified type. */

/* Obsolete, used only for backwards compatibility and libc5 compiles */
struct msqid_ds {
	struct ipc_perm msg_perm;
	struct msg *msg_first;	/* first message on queue,unused  */
	struct msg *msg_last;	/* last message in queue,unused */
	__kernel_time_t msg_stime;	/* last msgsnd time */
	__kernel_time_t msg_rtime;	/* last msgrcv time */
	__kernel_time_t msg_ctime;	/* last change time */
	unsigned long msg_lcbytes;	/* Reuse junk fields for 32 bit */
	unsigned long msg_lqbytes;	/* ditto */
	unsigned short msg_cbytes;	/* current number of bytes on queue */
	unsigned short msg_qnum;	/* number of messages in queue */
	unsigned short msg_qbytes;	/* max number of bytes on queue */
	__kernel_ipc_pid_t msg_lspid;	/* pid of last msgsnd */
	__kernel_ipc_pid_t msg_lrpid;	/* last receive pid */
};

/* Include the definition of msqid64_ds */
#include <asm/msgbuf.h>

/* message buffer for msgsnd and msgrcv calls */
struct msgbuf {
	long mtype;		/* type of message */
	char mtext[1];		/* message text */
};

/* buffer for msgctl calls IPC_INFO, MSG_INFO */
struct msginfo {
	int msgpool;
	int msgmap;
	int msgmax;
	int msgmnb;
	int msgmni;
	int msgssz;
	int msgtql;
	unsigned short msgseg;
};

/*
 * Scaling factor to compute msgmni:
 * the memory dedicated to msg queues (msgmni * msgmnb) should occupy
 * at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
 * up to 8MB       : msgmni = 16 (MSGMNI)
 * 4 GB            : msgmni = 8K
 * more than 16 GB : msgmni = 32K (IPCMNI)
 */
#define MSG_MEM_SCALE 32

#define MSGMNI    16   /* <= IPCMNI */	/* max # of msg queue identifiers */
#define MSGMAX  8192   /* <= INT_MAX */	/* max size of message (bytes) */
#define MSGMNB 16384   /* <= INT_MAX */	/* default max size of a message queue */

/* unused */
#define MSGPOOL (MSGMNI * MSGMNB / 1024)	/* size in kbytes of message pool */
#define MSGTQL  MSGMNB		/* number of system message headers */
#define MSGMAP  MSGMNB		/* number of entries in message map */
#define MSGSSZ  16		/* message segment size */
#define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ)	/* max no. of segments */
#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)

#ifdef __KERNEL__
#include <linux/list.h>

/* one msg_msg structure for each message */
struct msg_msg {
	struct list_head m_list;
	long m_type;
	int m_ts;		/* message text size */
	struct msg_msgseg *next;
	void *security;
	/* the actual message follows immediately */
};

/* one msq_queue structure for each present queue on the system */
struct msg_queue {
	struct kern_ipc_perm q_perm;
	time_t q_stime;		/* last msgsnd time */
	time_t q_rtime;		/* last msgrcv time */
	time_t q_ctime;		/* last change time */
	unsigned long q_cbytes;	/* current number of bytes on queue */
	unsigned long q_qnum;	/* number of messages in queue */
	unsigned long q_qbytes;	/* max number of bytes on queue */
	pid_t q_lspid;		/* pid of last msgsnd */
	pid_t q_lrpid;		/* last receive pid */

	struct list_head q_messages;
	struct list_head q_receivers;
	struct list_head q_senders;
};

/* Helper routines for sys_msgsnd and sys_msgrcv */
extern long do_msgsnd(int msqid, long mtype, void __user * mtext,
		      size_t msgsz, int msgflg);
extern long do_msgrcv(int msqid, long *pmtype, void __user * mtext,
		      size_t msgsz, long msgtyp, int msgflg);

#endif /* __KERNEL__ */

#endif /* _LINUX_MSG_H */
